BLM Data from the Collimator tests in SPS

BLM Data from the Collimator tests in SPS and TT 40 B. Dehning, F. Ferioli, E. B. Holzer, L. Jensen, L. Ponce and the Collimator Team 26. 11. 2004 Collimation WG Meeting, CERN 11/26/2004, Coll. WG Meeting E. B. Holzer 1

SPS BA 5 11/26/2004, Coll. WG Meeting E. B. Holzer 2

8 Ionization Chambers 11/26/2004, Coll. WG Meeting E. B. Holzer 3

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B B D D Left out Right in C A Left in / Right in Left in Right in Smaller gap Left in / Right out C A 11/26/2004, Coll. WG Meeting E. B. Holzer 6

Left in / Right out B D Left in Right in Smaller gap B C D Left in Right in C A Left out / Right in 11/26/2004, Coll. WG Meeting E. B. Holzer A 7

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Activation? Factor 5000 reduction in signal after 4 seconds t [s] 11/26/2004, Coll. WG Meeting E. B. Holzer 9

Activation measurements in the SPS • • Lit: G. Ferioli, R. L. Keizer, Analysys of the induced radioactivity in the SPS extraction channels during 1994, SL/Note 95 -06 (BT) Ionisation chamber based measurements during the fast extraction (SPS LSS 6) and after to determine the remaining activation Location of monitors: near kicker magnets and septum's Ratio between fluence of losses and activation 2000 11/26/2004, Coll. WG Meeting E. B. Holzer 10

Decay constants • Two decay constants – t 1: 1. 75 s – t 2: 278 s 11/26/2004, Coll. WG Meeting E. B. Holzer 11

TT 40 11/26/2004, Coll. WG Meeting E. B. Holzer 12

• BLM 1 – BLM 4: ionization chambers • BLM 5: SEM (no calibration) BLM 5 BLM 3 BLM 2 BLM 1 BLM 4 11/26/2004, Coll. WG Meeting E. B. Holzer 13

Number of electron pairs produced (35 e. V) per litre by 4 X 72 bunches, at floor level. Scale in cm. From M. Magistris. Signal for 4 batches: 11/26/2004, Coll. WG Meeting Measured Simulated BLM 1 3 E 13 ~ same BLM 2 4 E 13 ~ same BLM 3 8 E 13 (scaled) ~ same BLM 4 2 E 14 (scaled) ~ OK E. B. Holzer 14

1 - 4 Batches on both Collimator Jaws and the TED BLM signal Collimator TED BLM signal # protons 11/26/2004, Coll. WG Meeting E. B. Holzer 15

BLM signal / # protons Scanning the Impact Position on the Jaws BLM signal Distance from surface [mm] 11/26/2004, Coll. WG Meeting E. B. Holzer 16

Summary • No activation observed (Signal decreases by at least a factor 5000 when collimator moves out). • “Tails” in distributions are from the beam. • BLM signal is linear with proton intensity. • Left-right asymmetry of the shower depends on the collimator gap size and gap position. • Slight top-bottom asymmetry? • BLM signal depends on the impact position on the jaw. • Compares ~ OK with simulations (TT 40). • Further analysis … 11/26/2004, Coll. WG Meeting E. B. Holzer 17